MPLS S. Boutros
Internet-Draft S. Bryant
Intended status: Standards Track S. Sivabalan
Expires: July 11, 2009 G . Swallow
D. Ward
Cisco Systems
January 7, 2009
Definition of ACH TLV Structure
draft-bryant-mpls-tp-ach-tlv-00
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Abstract
In some application of the associated channel header (ACH), it is
necessary to have to ability to include a set of TLVs to provide
additional context information for the ACH payload. This document
describes the TLV structure and defines a number of TLV types.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC2119 [1].
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. ACH TLV . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. ACH TLV Header . . . . . . . . . . . . . . . . . . . . . . 4
2.2. ACH TLV Object . . . . . . . . . . . . . . . . . . . . . . 4
3. ACH TLV Object Definitions . . . . . . . . . . . . . . . . . . 5
3.1. The Null TLV Object . . . . . . . . . . . . . . . . . . . 5
3.2. Type FEC128PWv4 . . . . . . . . . . . . . . . . . . . . . 5
3.3. Type FEC128PWv6 . . . . . . . . . . . . . . . . . . . . . 6
3.4. Type FEC129PWv4 . . . . . . . . . . . . . . . . . . . . . 6
3.5. Type FEC129PWv6 . . . . . . . . . . . . . . . . . . . . . 7
3.6. Type ConnName . . . . . . . . . . . . . . . . . . . . . . 7
3.7. Path-list . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1. Normative References . . . . . . . . . . . . . . . . . . . 9
6.2. Informative References . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10
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1. Introduction
In some application of the associated channel header (ACH) [2] as
generalized in [9] (GACH) it is necessary to have to ability to
include a set of TLVs to provide additional context information for
the ACH payload. One use of these TLVs to identify the source and/or
intended destination of the ACH payload for use in transport
networks. However the use of this construct is not limited to
providing addressing information nor is the applicability restricted
to transport network applications.
Additionally GACH TLVs may be embedded with GACH TLVs to form higher
level constructs. For example a path-list TLV is a TLV which
contains a list of address TLVs of appropriate address type.
2. ACH TLV
This section describes the structure of the set of TLVs that MAY
follow an ACH. It then describes the structure of a ACH TLV object.
An ACH TLV header MUST follow an ACH if the ATLV bit is set in the
ACH [9]. Figure 2 shows the structure of a packet payload when an
ACH with the ATLV bit set.
+---------------------------------------------+
| Associated Channel Header with ATLV bit = 1 |
+---------------------------------------------+
| ACH TLV Header |
+---------------------------------------------+
| |
. One or more ACH TLV .
. .
| |
+---------------------------------------------+
| |
. ACH Payload as defined by ACH Type .
| |
+---------------------------------------------+
Figure 1: ACH TLV Structure
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2.1. ACH TLV Header
The ACH TLV Header defines the length of the set of ACH TLVs that
follow ACH header.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: ACH TLV Header
The length field specifies the length in octets of the complete set
of TLVs that follow the ACH TLV header. A length of zero indicates
that no ACH TLVs follow this header.
The reserved field is for future use and must be set to zero on
transmission and ignored on reception.
2.2. ACH TLV Object
The ACH TLV object consists of a 16 bit type field, followed by a 16
bit length field which specifies the number of octets that follow the
length field. This is followed zero or more octets of value
information.
The semantics of the value information are defined by the ACH TLV
Type as recorded in the ACH TLV Type registry.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ACH TLV Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Value ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: ACH TLV Object
Most of the ACH TLV types specified by this document are common
address types which need no need no further explanation. Any types
which are not simple addresses are described in the following
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section.
3. ACH TLV Object Definitions
This section provides further definition for a number of ACH TLV
objects.
3.1. The Null TLV Object
The Null TLV provides an OPTIONAL mechanism of restoring 32bit
alignment of the following element in the packet and also provides an
OPTIONAL mechanism to reserve space in the packet to be used by TLV
objects that will be written by LSR that perform some operation on
the packet at a later time. For example it might be used to reserve
space for a record route operation.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Value = 0 ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Null TLV Object
3.2. Type FEC128PWv4
This TLV contains a non-zero 32-bit pseudowire connection ID (PW ID)
as specified in Section 5.2 of [3] that terminates on a PE identified
by an IPv4 address.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = FEC128PWv4 | Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PW ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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3.3. Type FEC128PWv6
This TLV contains a non-zero 32-bit pseudowire connection ID (PW ID)
as specified in Section 5.2 of [3] that terminates on a PE identified
by an IPv6 address.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = FEC128PWv4 | Length = 24 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ IPv6 Address ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PW ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.4. Type FEC129PWv4
This TLV contains the Generalized ID FEC Element as specified in
Section 5.3.2 of [3] (i.e. The complete structure containing the
AGI, SAII and TAII in the referenced section) that terminates on a PE
identified by an IPv4 address.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = FEC129PWv4 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AGI Type | Length | Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ AGI Value (contd.) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII Type | Length | Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ SAII Value (contd.) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII Type | Length | Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ TAII Value (contd.) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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3.5. Type FEC129PWv6
This TLV contains the Generalized ID FEC Element as specified in
Section 5.3.2 of [3] (i.e. The complete structure containing the
AGI, SAII and TAII in the referenced section) that terminates on a PE
identified by an IPv6 address.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = FEC129PWv6 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AGI Type | Length | Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ AGI Value (contd.) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII Type | Length | Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ SAII Value (contd.) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII Type | Length | Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ TAII Value (contd.) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.6. Type ConnName
This is an octet string that identifies the name of the connection.
The encoding of the octets and the and the semantics of the string
are outside the scope of this document.
3.7. Path-list
This TLV contains a list of identifiers that are associated with the
path of the packet. It consists of a TLV that identifies this is a
path-list TLV with a value that consists of a set of address TLVs.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = Path-list | Length = var |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = AddressX | Length = var |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Address ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = AddressX | Length = var |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Address ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
By way of further illustration the following is a path-list that
contains 3 IPv4 addresses.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = path-list | Length = 24 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = IPv4DA | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = IPv4DA | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = IPv4DA | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
A path-list may contain a Null TLV.
4. Security Considerations
This specification defines a mechanism to identify a set of protocol
parameters. The necessary security considerations will be described
in the definition of the protocols that uses these parameters.
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5. IANA Considerations
IANA is requested create a new registry called ACH TLV Registry. The
allocation policy for this registry is IETF consensus.
The ACH TLV Registry should be initialized with the following values:
Name Type Length Description Definition Reference
(octets)
Null 0 3 Null TLV This Draft This Draft
IPv4DA 1 4 IPv4 Destination Addr RFC791 This Draft
IPv4SA 2 4 IPv4 Source Addr RFC791 This Draft
IPv6DA 3 16 IPv6 Destination Addr RFC1883 This Draft
IPv6SA 4 16 IPv6 Source Addr RFC1883 This Draft
MACSA 5 6 IEEE Mac Destination Addr This Draft
MACDA 6 6 IEEE Mac Destination Addr This Draft
NSAPSA 7 var OSI NSAP Source Addr ISO8348 This Draft
NSAPDA 8 var OSI NSAP Source Addr ISO8348 This Draft
FEC128PWv4 9 12 FEC 128 PW Identifier v4 PE RFC4447 This Draft
FEC128PWv6 10 24 FEC 128 PW Identifier v6 PE RFC4447 This Draft
FEC129PWv4 11 var FEC 129 PW Identifier v4 PE RFC4447 This Draft
FEC129PWv6 12 var FEC 129 PW Identifier v6 PE RFC4447 This Draft
ConnName 13 var Octet connection name This draft This Draft
Path-list 14 var Path-list This draft This Draft
6. References
6.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Bryant, S., Swallow, G., Martini, L., and D. McPherson,
"Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use
over an MPLS PSN", RFC 4385, February 2006.
[3] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron,
"Pseudowire Setup and Maintenance Using the Label Distribution
Protocol (LDP)", RFC 4447, April 2006.
[4] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1981.
[5] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6)
Specification", RFC 1883, December 1995.
[6] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label
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Switched (MPLS) Data Plane Failures", RFC 4379, February 2006.
[7] Allan, D. and T. Nadeau, "A Framework for Multi-Protocol Label
Switching (MPLS) Operations and Management (OAM)", RFC 4378,
February 2006.
[8] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., Farinacci, D.,
Li, T., and A. Conta, "MPLS Label Stack Encoding", RFC 3032,
January 2001.
6.2. Informative References
[9] Bocci, M., Vigoureux, M., Swallow, G., Ward, D., and R.
Aggarwal, "MPLS Generic Associated Channel",
draft-ietf-mpls-tp-gach-gal-01 (work in progress), January 2009.
Authors' Addresses
Sami Boutros
Cisco Systems
Phone:
Fax:
Email: sboutros@cisco.com
URI:
Stewart Bryant
Cisco Systems
Phone:
Fax:
Email: stbryant@cisco.com
URI:
Siva Sivabalan
Cisco Systems
Phone:
Fax:
Email: msiva@cisco.com
URI:
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George Swallow
Cisco Systems
Phone:
Fax:
Email: swallow@cisco.com
URI:
David Ward
Cisco Systems
Phone:
Fax:
Email: dward@cisco.com
URI:
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